Dice Theory

Astable circuits

Counting circuits

Seven Segment Displays

Electronic Dice Circuits

(Source: Micro-electronics Yellow Book)

How it works: •The 4047B multi-vibrator is used as an astable circuit. •When switches, S1 and S2 are closed, current charges C1 through R1 producing a high output at pin 13 of the 4047B. C1 is then discharged resulting in a low output at pin 13. •This process repeats, producing a pulse train out of pin 13. •The train of pulses feed into the clock input (pin 14) of the 4017 decade counter. Each pulse creates a high output on one of the LEDs. Each subsequent pulse then moves the high output to the next LED. •When switch S2 is opened, one LED is left lit up, producing a “random” selection. •The high frequency pulse train makes it appear that all LEDs are on, when it in fact they are just pulsing very quickly.